“Today we made the decision to put Ellenborough Lewis to sleep. We placed him under general anaesthesia this morning to assess his burns injuries and change the bandages,” read a statement on the hospital’s official Facebook page.

“We recently posted that ‘burns injuries can get worse before they get better’. In Ellenborough Lewis’s case, the burns did get worse, and unfortunately would not have gotten better.

“The Koala Hospital’s number one goal is animal welfare, so it was on those grounds that this decision was made. We thank you for your ongoing support.”

Footage of Lewis’ ordeal went viral last week when Doherty found him struggling to escape a bushfire near Long Flat in New South Wales. She took the shirt off her own back and risked her safety by entering the blaze to save Lewis by wrapping the whimpering animal in her top and pouring water over it.

She then took the badly injured koala 49 kilometres to the Port Macquarie Koala Hospital where he was named after Toni’s grandson and taken into home care.

“It was terrifying to see him just come out of the flames and he looked so defenceless running along the road,” Doherty told Nine News.

“I knew I needed to put something around him as I ran to the tree, so I just took off my shirt and covered him with it. I just tried to get him out of the fire, it was so hot and so frightening.”

ReutersToni Doherty in Long Flat risked her safety to saved scorched koala from NSW bushfires.

ReutersShe saved the burning koala near Port Macquarie with the shirt off her own back.

Port Macquarie Koala Hospital Clinical director Cheyne Flanagan later said the koala had been put on fluids and oxygen and was “probably the worst one” they had in their care.

“He’s got, what we call, partial thickness burns and there’s one little spot of full thickness. So he’s got really badly burnt hands and feet, he’s got burns under his arms, his nose is burnt and a bit of his private parts are burnt as well, and he is singed all over,” she said.

Nine NewsLewis had been reunited with Toni Doherty who rescued him from a NSW bushfire near Long Flat, 49 kilometres west of Port Macquarie.

The country’s koala population has been a major victim of the flames, with more than 350 of the marsupials feared killed in a major habitat. Warmer weather brought by climate change threatens to worsen conditions for koalas, as deforestation has narrowed habitable areas, said James Tremain of the Nature Conservation Council of New South Wales.

“Devastating bushfires are going to knock out some of these key population centres, but so will increasing temperatures,” he said, by affecting the nutrition value of the leaves that are the animals’ sole food source.

A GoFundMe page for the koala hospital was launched on October 31 and has tremendously exceeded its $25,000 target, with over $1 million of donations recorded on its page.